This invention relates generally to portable crane apparatus, and more particularly to portable, folding crane apparatus of the bridge or gantry type.
There are many instances in which it is desirable to establish quickly and easily a temporary freight or load handling facility. Building contractors, for example, have a need for unloading building materials from trucks at a construction site, and freight transfer companies are often faced with the problem of loading or unloading freight at locations which do not have freight handling apparatus. The military has a particularly critical need for temporary freight handling facilities which may be easily and quickly erected in a field environment, as for supplying combat units, and which may be quickly disassembled and transported to other locations. Essential to such temporary facilities are portable cranes or other load handling apparatus. Although cranes or other lifting devices may sometimes be provided on the vehicles used to transfer freight, this is not practical for some types of vehicles, tractor-trailer trucks, for example, and, in any event adds unnecessary complication and expense to the vehicle. Accordingly, it is desirable to provide separate portable crane apparatus which may be easily transported to a temporary freight handling facility and erected, and then quickly collapsed and moved to another location. Although portable cranes, both self-propelled and otherwise, are known, known cranes have a number of disadvantages for temporary load handling facilities, particularly in a military environment.
It is desirable to provide crane apparatus which avoids these and other disadvantages of known apparatus, and it is to this end that the present invention is directed.